Quantitative pharmacokinetic and biodistribution studies for fluorescent imaging agents

Area of Science:

• Biomedical Imaging
• Pharmacokinetics
• Fluorescence Spectroscopy

Background:

• Accurate quantification of fluorescent agents in vivo is vital for pharmacokinetic and biodistribution studies.
• Existing fluorescence imaging methods often struggle to account for variations in tissue optical properties and sample volumes.
• A need exists for simplified, reliable methods to quantify fluorescent agents in biological samples.

Purpose of the Study:

• To develop and validate a straightforward fluorescence imaging method for quantifying fluorescent agents in whole blood and homogenized tissues.
• To assess the accuracy and reliability of the developed method using two distinct fluorescent agents.
• To establish the lower limit of quantification (LLOQ) for the tested agents.

Main Methods:

• Utilized wide-field fluorescence imaging for simultaneous quantification of mean fluorescence intensity.
• Employed glass capillary tubes for sample preparation of whole blood and homogenized tissues.
• Developed tissue-specific calibration curves to account for variations in optical properties and sample matrices.
• Quantified two fluorescent agents: ABY-029 and IRDye 680LT.

Main Results:

• Achieved high linearity for all calibration curves, with a mean R² of 0.99 ± 0.01 and RMSE of 0.12 ± 0.04.
• Demonstrated that tissue-specific calibration curves are necessary for precise concentration recovery.
• Determined LLOQ values below 0.3 nM for ABY-029 and below 0.4 nM for IRDye 680LT.

Conclusions:

• The developed fluorescence imaging method provides a simple and accurate approach for quantifying fluorescent agents in blood and tissues.
• Tissue-specific calibration is essential for reliable concentration measurements, improving pharmacokinetic and biodistribution analyses.
• This method offers a valuable tool for preclinical research involving fluorescently labeled compounds.